Dataset Information

HACE1: A novel repressor of RAR transcriptional activity.

ABSTRACT: The diverse biological actions of retinoic acid (RA) are mediated by RA receptors (RARs) and retinoid X receptors (RXRs). While the coregulatory proteins that interact with the ligand-dependent AF-2 in the E region are well studied, the ligand-independent N-terminal AF-1 domain-interacting partners and their influence(s) on the function of RARs are poorly understood. HECT domain and Ankyrin repeat containing E3 ubiquitin-protein ligase (HACE1) was isolated as a RARbeta(3) AB region interacting protein. HACE1 interacts with RARbeta(3) both in in vitro GST pull-down and in cell-based coprecipitation assays. The interaction sites map to the N terminus of RARbeta(3) and the C terminus of HACE1. HACE1 functionally represses the transcriptional activity of RARalpha(1), RARbeta isoforms 1, 2, and 3, but not RARgamma(1) in luciferase reporter assays. In addition, HACE1 represses the endogenous RAR-regulated genes CRABP II, RIG1 and RARbeta(2), but not RAI3 in CAOV3 cells. Mutation of the putative catalytic cysteine (C876 of LF HACE1), which is indispensable for its E3 ubiquitin ligase activity, does not alter the repressive effect of HACE1 on the transcriptional activity of RARbeta(3). On the other hand, HACE1 inhibits the RA dependent degradation of RARbeta(3). It is possible that the repression of RAR-regulated transcription by HACE1 is due to its ability to inhibit the RA-dependent degradation of RARs.

SUBMITTER: Zhao J

PROVIDER: S-EPMC2736627 | biostudies-literature | 2009 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

HACE1: A novel repressor of RAR transcriptional activity.

Zhao Jianhua J Zhang Zhenping Z Vucetic Zivjena Z Soprano Kenneth J KJ Soprano Dianne Robert DR

Journal of cellular biochemistry 20090601 3

The diverse biological actions of retinoic acid (RA) are mediated by RA receptors (RARs) and retinoid X receptors (RXRs). While the coregulatory proteins that interact with the ligand-dependent AF-2 in the E region are well studied, the ligand-independent N-terminal AF-1 domain-interacting partners and their influence(s) on the function of RARs are poorly understood. HECT domain and Ankyrin repeat containing E3 ubiquitin-protein ligase (HACE1) was isolated as a RARbeta(3) AB region interacting p ...[more]

PMID: 19350571

Similar Datasets

Project description:BackgroundNRP/B, a family member of the BTB/Kelch repeat proteins, is implicated in neuronal and cancer development, as well as the regulation of oxidative stress responses in breast and brain cancer. Our previous studies indicate that the NRP/B-BTB/POZ domain is involved in the dimerization of NRP/B and in a complex formation with the tumor suppressor, retinoblastoma protein. Although much evidence supports the potential role of NRP/B as a tumor suppressor, the molecular mechanisms of NRP/B action on E2F transcription factors have not been elucidated.MethodsThree-dimensional modeling of NRP/B was used to generate point mutations in the BTB/Kelch domains. Tet-on inducible NRP/B expression was established. The NRP/B deficient breast cancer cell line, MDA-MB-231, was generated using lentiviral shNRP/B to evaluate the effect of NRP/B on cell proliferation, invasion and migration. Immunoprecipitation was performed to verify the interaction of NRP/B with E2F and histone deacetylase (HDAC-1), and the expression level of NRP/B protein was analyzed by Western blot analysis. Changes in cell cycle were determined by flow cytometry. Transcriptional activities of E2F transcription factors were measured by chloramphenicol acetyltransferase (CAT) activity.ResultsEctopic overexpression of NRP/B demonstrated that the NRP/B-BTB/POZ domain plays a critical role in E2F-mediated transcriptional activity. Point mutations within the BTB/POZ domain restored E2-promoter activity inhibited by NRP/B. Loss of NRP/B enhanced the proliferation and migration of breast cancer cells. Endogenous NRP/B interacted with E2F and HDAC1. Treatement with an HDAC inhibitor, trichostatin A (TSA), abolished the NRP/B-mediated suppression of E2-promoter activity. Gain or loss of NRP/B in HeLa cells confirmed the transcriptional repressive capability of NRP/B on the E2F target genes, Cyclin E and HsORC (Homo sapiens Origin Recognition Complex).ConclusionsThe present study shows that NRP/B acts as a transcriptional repressor by interacting with the co-repressors, HDAC1, providing new insight into the molecular mechanisms of NRP/B on tumor suppression.

Dataset Information

HACE1: A novel repressor of RAR transcriptional activity.

Publications

HACE1: A novel repressor of RAR transcriptional activity.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets